A unit cell is a The smallest group of atoms which when regu

A unit cell is (a) The smallest group of atoms which when regularly repealed forms the crystal (b) A group of atoms which form a cubic arrangement (c) A unit cube containing the smallest number of atoms (d) The smallest group of atoms which will diffract X-rays. Crystalline materials atoms: (a) are pack in periodic (b) have no periodic packing (c) tend to be densely packed (d) a, c ATOMIC PACKING FACTOR (Volume of atoms in unit cell/Volume of unit cell) tor HCP crystal structure (a) 0.52 (b) 0.68 (c) 0.74 (d) 1 Single crystal is Anisotropic: (a) True (b) False (c) Depends on type of unit cell (d) None Polycrystalline material are anisotropic: (a) True (b) False (c) If grains are textured (d) If grains are randomly oriented

Solution

8)               (b)

9)              (d)

10)             (c)

11)              (c)

12)             (d)